水溶性量子点碲化镉测定同型半胱氨酸的研究

以巯基丙酸为稳定剂,在水溶液中一步合成了CdTe量子点,以该量子点为荧光探针,基于荧光增敏法对同型半胱氨酸(Hcy)进行选择性测定,考察了缓冲体系、缓冲液浓度、缓冲液pH值、反应时间、量子点浓度等多种因素的影响.在0.05 mol/L、pH 8.8的磷酸二氢钠-磷酸氢二钠缓冲液中,当量子点浓度为1.2 mmol/L、反应时间为10 min时,该方法的线性区间为0.1 ～60 μmol/L,检出限为8×10-8 mol/L.     

玻璃微流控芯片十二烷基硫酸钠无胶筛分电泳测定免疫球蛋白片段分子量

通过实验优化了葡聚糖筛分介质和运行缓冲溶液的浓度,采用十二烷基硫酸钠(SDS)无胶筛分电泳分离体系(10%(w/v)葡聚糖,0.1%SDS,10%甘油,0.2mol/LTris-硼砂,pH8.3的缓冲液)在自制的玻璃微流控芯片上高效分离了BODIPY衍生的蛋白质分子量标准样品,连续6次电泳所得迁移时间的相对标准偏差均小于0.50%。以6种蛋白质分子量的对数对其迁移时间作图,线性回归良好(r=0.994)。采用该芯片电泳分析体系对免疫球蛋白G不同片段的分子量进行了测定,所得结果与实际基本相符。     

贵金属元素电化学分析研究(Ⅸ)——微量铑的阳极溶出伏安法测定

Shifris B.J.等用伏安法在0.5mol/LHCl(含0.1mmol/LHg~(2+))支持电解质中,进行了Cu-Ni精矿中Rh、Ir的连续测定,但灵敏度较低,只能测至1μmol/L。作者曾用HgCl_2-HCl-乙二胺体系测定Rh(Ⅲ),检出限为10ng。 本文进一步发现铑离子在H_2SO_4-HgCl_2介质中,具有稳定而尖锐的阳极溶出峰(见图1)。图中Rh(Ⅲ)峰右侧出一微小平台是由于     

双酚A在壳聚糖石墨烯复合膜电化学传感器上的电化学行为及测定

采用hummers法制备了石墨烯,以碳糊电极为基底电极采用滴涂法制备了壳聚糖石墨烯复合膜电化学传感器(CTS/GR/CPE),并利用循环伏安法和线性扫描溶出伏安法研究了双酚A在电化学传感器上的电化学行为。在pH 7.4的磷酸盐缓冲液中,于-0.1V富集180s后,该电化学传感器对双酚A具有良好的电催化作用,于0.564V处有一灵敏的氧化峰,线性范围为1.00×10-6～7.00×10-5mol/L和7.00×10-5～1.00×10-3mol/L,检出限(S/N=3)为1.00×10-7mol/L。方法用于塑料制品中溶出双酚A的测定,回收率为96.4%～100.5%。     

碳点-钙黄绿素荧光共振能量转移体系在山奈素检测中的应用研究

研究了碳点(CDs)-钙黄绿素(CA)能量转移体系,并利用该体系建立了测定山奈素(KF)的新方法。在λex=320 nm下,pH 8.0的磷酸氢二钠-柠檬酸缓冲液中,CDs与CA能发生有效的能量转移,使得CA的荧光增强,而KF的加入则可有效猝灭CA的荧光,且在一定范围内CA的荧光猝灭值与KF的加入量呈良好的线性关系,基于此建立了测定KF的新方法。在最佳实验条件下,方法的线性范围为1.0×10-8~3.4×10-6mol/L,检出限为3.33×10-9mol/L。方法应用于复方金银花颗粒中KF含量的测定,回收率为98.4%~103.5%,RSD(n=6)不大于2.7%。     

多壁碳纳米管修饰乙炔炭黑微电极测定碘

以多壁碳纳米管修饰乙炔炭黑微电极为工作电极,研究了碘离子在该修饰电极上的阳极溶出伏安特性。在0.1 mol/L KH2PO4 缓冲液(pH4.0)中,从200 mV以200 mV/s的速率正向扫描至1200 mV,碘离子在570 mV处出现一灵敏的阳极溶出峰。峰电流与碘离子的浓度在2.0×10-6～1.0×10-3 mol/L范围内呈良好的线性关系,检出限为8.0×10-7 mol/L。方法用于食盐中碘含量的测定,结果满意。     

黑曲霉脂肪酶的耦合固定化及特性

研究了吸附-絮凝耦合的方法固定脂肪酶的工艺条件.结果表明:在33℃下,用0.03mol/L的磷酸二氢钾?氢氧化钠缓冲液控制体系pH为7.0,酶与树脂(质量比1∶8)作用吸附1h后,用0.2mL絮凝剂聚丙烯酰胺(w(PAM)=0.5%)处理,得到活力较高的固定化脂肪酶.固定化酶最适pH9.0,最适温度为45℃,活力为405U/g,酶活回收率可以达到40%.固定化脂肪酶制备简便,可重复使用,稳定性较高.     

高效液相色谱-荧光检测法测定环境水中的苯胺和苯酚

建立了用高效液相色谱荧光检测法同时测定环境水中苯胺和苯酚的分析方法。色谱柱为EclipseXDB C8(4.6mmi.d.×150mm,5μm),流动相为甲醇 磷酸盐缓冲液(0.1mol/L磷酸二氢钾 0 1mol/L磷酸氢二钠,pH6.87)V(甲醇)∶V(磷酸盐缓冲液)=50∶50,流速1 0mL/min,柱温25℃,检测波长0minλex/λem=230/340nm(测定苯胺),3.5minλex/λem=215/300nm(测定苯酚)。测定苯胺的线性范围0.2～120ng,r=0.9999,检出限0.01ng;测定苯酚的线性范围0.4～500ng,r=0.9998,检出限0.02ng,回收率98.1%～101.2%。该方法已用于对环境水中苯胺和苯酚的测定。     

毛细管电泳电化学发光法分离检测西咪替丁

建立了以三联吡啶钌为发光体系的毛细管电泳电化学发光(CE-ECL)检测系统,并应用于分离和测定西咪替丁片剂中西咪替丁的含量。考察了检测电位,三联吡啶钌(Ru(bpy)32+)的溶液浓度,缓冲液的pH和溶液浓度,分离电压、进样电压与进样时间等因素对分离检测的影响。结果表明:在检测电位1.18V,Ru(bpy)32+溶液浓度为5 mmol/L,磷酸盐缓冲液(PBS)25 mmol/L(pH 7.8),进样时间10 s,进样电位10 kV,运行电位15 kV下,测得西咪替丁线性范围为2.8×10-6~4.0×10-4mol/L,检出限为1.2×10-7mol/L(S/N=3)。对1.0×10-5mol/L的西咪替丁标准溶液连续测定5次,电化学发光强度和迁移时间的RSD分别为3.9%和1.5%。方法已应用于西咪替丁片剂中西咪替丁含量的测定。     

羧甲基壳聚糖-熊果酸纳米载药粒子的合成及性能研究

选择水溶性羧甲基壳聚糖(CMCS)-聚乙二醇(PEG)作为载药分子链,叶酸(FA)作为靶向分子,利用pH感应酯键连接药物分子熊果酸(UA),通过吸附自组装包裹10-羟基喜树碱(HCPT),合成了一种抗肿瘤叶酸-聚乙二醇-羧甲基壳聚糖-熊果酸/10-羟基喜树碱~1H-NMR及TEM表征FA-PEG-CMCS-UA/HCPT纳米药物粒子结构和形态。核磁共振谱表明,UA是以酯键连接CMCS,透射电镜图显示纳米粒子呈球形;UA和HCPT的载药量分别为(6.4±0.1)%和(14.1±0.2)%;在pH值为7.4和5.5且PBS缓冲液中体外药物释放达到330h时,UA的累积释放率分别为70.2%和85.1%,HCPT的累积释放率达到73.8%和86.6%。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.